TOF-TOF with high resolution precursor selection and multiplexed MS-MS

Abstract

The present invention comprises apparatus and methods for rapidly and accurately determining mass-to-charge ratios of molecular ions produced by a pulsed ionization source, and for fragmenting substantially all of the molecular ions produced while rapidly and accurately determining the intensities and mass-to-charge ratios of the fragments produced from each molecular ion.

Description

BACKGROUND OF THE INVENTION[0001]Many applications require accurate determination of the molecular masses and relative intensities of metabolites, peptides and intact proteins in complex mixtures. Time-of-flight (TOF) with reflecting analyzers provides excellent resolving power, mass accuracy, and sensitivity at lower masses (up to 5-10 kda), but performance is poor at higher masses primarily because of substantial fragmentation of ions in flight. At higher masses, simple linear TOF analyzers provide satisfactory sensitivity, but resolving power and mass accuracy are low. A TOF mass analyzer combining the best features of reflecting and linear analyzers is required for these applications.[0002]An important advantage of TOF mass spectrometry (MS) is that essentially all of the ions produced are detected, unlike scanning MS instruments. This advantage is lost in conventional MS-MS instruments where each precursor is selected sequentially and all non-selected ions are lost. This limita...

AI Technical Summary

Benefits of technology

"The present invention is a mass spectrometer that can quickly and accurately determine the mass-to-charge ratios of molecules produced by a pulsed ion source. It uses a symmetrical ion mirror array and a vacuum housing to select and direct ions to a detector. The instrument also includes a timed-ion-selector and an ion deflector to improve the accuracy of the measurements. The mass spectrometer can identify peptides and other molecules in complex mixtures and can generate high-quality MS-MS spectra at unprecedented speed. The combination of high-resolution precursor selection with high laser rate and multiplexing allows for the identification of peptides at the 10 attomole / uL level. The instrument is designed for single-mode operation and can generate MS-MS spectra on detected peptides at the 10 attomole / uL level. The technical effects of the invention include improved accuracy and sensitivity in mass spectrometry and faster and more reliable identification of molecules in complex mixtures."

Problems solved by technology

Time-of-flight (TOF) with reflecting analyzers provides excellent resolving power, mass accuracy, and sensitivity at lower masses (up to 5-10 kda), but performance is poor at higher masses primarily because of substantial fragmentation of ions in flight.

At higher masses, simple linear TOF analyzers provide satisfactory sensitivity, but resolving power and mass accuracy are low.

All of these improvements will have limited impact unless the instruments are reliable, cost-effective, and very easy to use.

All of these approaches have been used to successfully produce MS-MS spectra following MALDI ionization, but each suffers from serious limitations that have stalled widespread acceptance.

Furthermore, the sensitivity, speed, resolution, and mass accuracy for the first two techniques are inadequate for many applications.

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